This application relates generally to the field of medical devices known as bone distractors, devices that continuously or incrementally separate two bone segments. More particularly, this application relates to such devices that utilize tensioned members to provide the distraction force.
In some bone distraction procedures it is desirable to provide a continuously applied separation force rather than an incrementally applied separation force. It is also often desirable to provide a distraction device in which the distraction force is adjustable. A distraction device having both of these characteristics is particularly desirable for the correction of craniosynostosis, a condition that occurs in infants as the brain develops and grows in size. The skull bones of an infant are initially joined together by fibrous tissue, known as sutures, which extend as the brain grows and later ossify once brain growth decreases. In craniosynostosis the sutures ossify too soon, with the premature fusion resulting in skull deformities that, beyond aesthetics, may adversely affect eyesight or breathing, or may even be life threatening.
To address this condition, surgery is performed to separate the prematurely fused cranial bones to allow for expansion. However, it is necessary to continuously distract the bone portions to prevent re-fusion before the desired final size and shape of the cranium is reached.
It is an object of this invention to provide a distraction device that is especially suitable for use in the treatment of craniosynostosis, wherein the distractor provides a continuous distraction force and is force adjustable, both initially and during the treatment process.